Issue 11, 2024

A highly crystalline donor enables over 17% efficiency for small-molecule organic solar cells

Abstract

The development of novel small-molecule donors is crucial for achieving highly efficient small-molecule organic solar cells (SM-OSCs). In this study, two small-molecule donors, B3TR and B2, were designed and synthesized. In comparison with B3TR, the skeleton of B2 includes an additional benzo[1,2-b:4,5-b′]dithiophene (BDT) unit, but lacks two alkylated thiophene units. Although both small-molecule donors exhibit similar absorption profiles in solution, B2 demonstrates stronger crystallinity and lower energetic disorder than B3TR. When it is blended with the non-fullerene acceptor BTP-eC9, it forms the B2:BTP-eC9 film exhibits a smaller π–π distance and a more favorable bulk heterojunction morphology. Interestingly, with an increase in solvent vapor annealing (SVA) time, B3TR shows a significant redshift in the absorption edge in the B3TR:BTP-eC9 film and an upshifted HOMO level. In contrast, B2 does not exhibit redshifts in the absorption edge in the B2:BTP-eC9 film and maintains an unchanged HOMO level. Consequently, the as-cast B3TR:BTP-eC9-based device achieves a PCE of 2.36%, with an open-circuit voltage (VOC) of 0.870 V. After SVA treatment, the B3TR:BTP-eC9-based SM-OSC attains a PCE of 14.8% with a significantly reduced VOC of 0.809 V. In contrast, the as-cast B2:BTP-eC9-based device exhibits a significantly high PCE of 9.8% with a VOC of 0.876 V. After SVA treatment, the B2:BTP-eC9-based device produces a superior PCE of 17.1%, with a slightly reduced VOC of 0.861 V. This study indicates that the development of highly crystalline donor materials is one of the promising strategies for achieving high-performance SM-OSCs.

Graphical abstract: A highly crystalline donor enables over 17% efficiency for small-molecule organic solar cells

Supplementary files

Article information

Article type
Paper
Submitted
25 Jan 2024
Accepted
16 Apr 2024
First published
17 Apr 2024

Energy Environ. Sci., 2024,17, 3927-3936

A highly crystalline donor enables over 17% efficiency for small-molecule organic solar cells

T. Zhang, C. An, P. Bi, K. Xian, Z. Chen, J. Wang, Y. Xu, J. Dai, L. Ma, G. Wang, X. Hao, L. Ye, S. Zhang and J. Hou, Energy Environ. Sci., 2024, 17, 3927 DOI: 10.1039/D4EE00400K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements